The nearly 4,000 members of the U.S. military who have died in Iraq were more than numbers. They were teammates and neighbors, schoolmates and brothers — people such as these:

•Cory Palmer and Rick James, Marines who came from the small town of Seaford, Del., and were killed within a week of each other in May 2006.

•John Byrd and Bradley Parker, graduates of North Marion High School in Fairmont, W.Va., who were killed within two weeks of each other in fall 2004.

•Joel House and Blair Emery, who played soccer together for most of their lives and were killed within seven months of each other last year. Their names will be inscribed together on the veterans monument in their native Lee, Maine.

Those who try to assess the meaning of their sacrifice do so at their peril. Andrew Olmsted, an Army major who wrote online about military life in Iraq for Denver's Rocky Mountain News, left an entry to run in case of his death. After he was killed Jan. 3 by a sniper, "Final Post" appeared the next day.

He asked "that no one try to use my death to further their political purposes. … My life isn't a chit to be used to bludgeon people to silence on either side. If you think the U.S. should stay in Iraq, don't drag me into it by claiming that somehow my death demands us staying in Iraq. If you think the U.S. ought to get out tomorrow, don't cite my name as an example of someone's life who was wasted."

Who will be the 4,000th fatality? That depends on whom you count. Just members of the U.S. military, or U.S. civilians working for the military? Only deaths caused by the enemy, or all U.S. military deaths? (USA TODAY, like the Pentagon, counts hostile and non-hostile deaths of uniformed military personnel.)

To complicate matters, soldiers often die in groups during battle, and it's often unclear exactly when and in what order they perish. The war's first four official U.S. fatalities, for instance, occurred in a helicopter crash in Kuwait.

Sequential numbering of individual deaths is often an illusion. On Sept. 6, 2004, the day the death toll passed 1,000, 12 people died, making it almost impossible to determine who was No. 1,000.

It can take days for military officials to receive, confirm and release casualty reports, making a sequential count in real time especially difficult.

When Army Pvt. Dustin Donica was killed in the last week of 2006, he was described by several news organizations as the 3,000th U.S. military fatality; at his funeral in Houston, the minister said, "Three thousand is not just a number to us anymore. It has a face now."

But it was not Donica's. There apparently was a miscount, by the Pentagon or news organizations or both. In retrospect, Donica was between 2,983 and 2,988 — six servicemembers died that day — not counting seven civilian Defense Department employees who'd died earlier in the war.

No one knows how many Iraqis have died in the war. In January, a report by the World Health Organization and the Iraqi government estimated that 151,000 might have died violently from the war's start through June 2006.

That was three times as high as the estimate for the same period by the organization Iraqi Death Count, and a fourth of an estimate published in the British science journal Lancet by a Johns Hopkins University research team.

Clark Dougan, an editor at the University of Massachusetts Press who has written on the Vietnam War, says the focus on the U.S. death toll has one unfortunate effect: "The impact of war is always measured in terms of U.S. fatals — and only U.S. fatals."

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